U.S. Pat. No. 3,723,283 comprehensively described a typical prior art system for plating metal onto selected portions of a moving strip of lead frame. Lead frame comprises a long strip of metal, sometimes delicate in structure, that is plated in various ways and then cut into small segments to form leads for electronic components such as integrated circuits. The above noted patent shows how the strip of lead frame is periodically advanced through the plating heads so subsequent portions of the strip may be plated. This physical movement, called indexing, is traditionally accomplished by inserting a pin into one of a series of holes in the edge, or rail, of the lead frame, and stroking it forward a set distance. However, as lead frames have become smaller and finer in structure, the forces of a pin pushing against the side of a tiny hole can become too concentrated to be borne by the delicate structure of the lead frame.